Numerous proposals have been made for providing indexing tabs, or incorporating indexing pages in large books such as dictionaries, directories and the like.
For example, in some cases, index tabs are actually incorporated on the pages themselves, or alternatively the pages may be die cut with indentations. These systems are relatively expensive and are only suitable for more or less permanent books such as dictionaries, where the price of the article justifies the extra cutting required.
In other forms of directories, particularly those such as telephone directories which are replaced yearly, the use of such indexing tabs, or indexing recesses, is not practical for various reasons. For example, it would greatly increase the cost of printing the directory, and this would have to be passed on to the consumer. Another factor is the quality of the paper. In most cases, such annual directories are produced on fairly cheap paper such that it becomes easily torn. Consequently, indexing tabs on such pages are virtually useless. Cutting out indexing recesses becomes too complicated.
Indexing systems are available which can be attached to certain types of directories and books. However, again, such tabs are usually attached to the pages themselves. Where the directory is printed on cheap paper, then the tabs are immediately torn off.
Clearly, there is a need for indexing in such directories, particularly as they increase in size every year. Preferably, however, such an indexing system should be provided as an extra feature, and not as part of the directory, which would simply increase the overall cost of the directory. In this way, it will become possible to supply an indexing system separately to the consumer who may then purchase it or not, as he wishes.